Propagation and transmission of action potentials Flashcards
Depolarization due to AP’s decay rapidly as distance from stimulation increases. Why?
because you don’t move a lot of ions when you depolarize a cell…
How are APs propagated?
Think about action potential as positive feedback mechanism.
Conduction velocity is dependent upon the ____ and ______ constants.
time
length
Time constant:
time to depolarize to 63% of max
smaller t, faster depolarization, faster conduction
Length constant:
How far the depolarization can travel before it drops below 63%.
If you want to move something quickly you want a thicker or thinner axon?
thicker
Layers and layers of cell membranes around an axon.
Myelin
Space between myelin is called what?
node of ranvier
What decreases the nerve?
Myelination!! It increases the length underneath the sheath, so it increases the length constant. Much higher concentration of ions, and makes AP’s jump between nodes. Decreases time constant.
What is a site of communication from one cell to another?
synapse
What is an electrical synapse?
gap junction, fast but no integration
what is a chemical synapse?
most common synapse, everything else not a gap junction, slow but allows integration. (inputs on a synapse to make a decision)
True/False: Electrical synapses can only move one way and chemical are bidirectional.
False, opposite
Neurotransmitters have to bind to receptors. why?
If you don’t have the receptor for the neurotransmitter the drug wont work.
Only neurotransmitter in a neuromuscular junction.
Ach Acetylcholine
